Furnace for boilers



2 Sheets-Sheet 2 J. A. FREIDAY FURNACE FOR BOILERS Filed'July' 21 1927 l A M 1 Oct. 31, 1933.

11v VEN TOR J4 r 4/?5/06 K Patented Oct. 31, 1933 UNITED STATES 1,932,455 FURNACE FOR BOILERS Jay A. Frciday, East Orange, N. J., assignor to, Thomas E. Murray, Brooklyn, N. Y.; Joseph Bradley Murray, Thomas E. Murray, J12, and John F. Murray, executors of said Thomas E.

Murray, deceased ApplicationJuly 21, 1927. Serial No. 207,331

2 Claims. (01. 110'2 8) The invention relates to improvements in boiler furnaces and aims particularly to provide for improvements in grates or bottom wallsfor such furnaces. While not limited thereto, the embodiment of the invention illustrated is particularly adapted for the burning of sawdust or wood in a finely divided state. The invention will be apparent from the following specification when read in connection with the accompanying dra" ings and the novel features will be defined with particularity in the appended claims. In the drawings Fig. 1 is a vertical section illustrating one embodiment of the invention;

Fig. 2 is a horizontal section on line 2-2 of Fig. 1;

Fig. 3 is a similar horizontal section showing a slight modification in the form of the stepped grate;

Fig. 4 is a vertical section similar to Fig. '1 but illustrating a modified arrangement;

Fig. 5 is a section on line 5- -5 of Fig. 4;

Fig. 6 is a view similar to Fig. 5 but showing slight modifications; v

Fig. 7 is an enlarged detail illustrating constructional features;

Fig. 8 is a similar detail of a modification.

Referring first to Figs. 1 to 3 inclusive, the furnace illustrated is provided with suitable upright walls 10 which enclose a combustion chamber 12 above which is located a bank of boiler tubes 14 connected to suitable headers 16 and 18 which in turn are connected by tubes 20 and 22 to the steam drum 24. Baffle plates 26 and 28 are provided to compel the products of combustion to follow the circuitous path from the combustion chamber 12 to the stack 30 as indicated by the arrows. The furnace is adapted to be fired preferably by sawdust or finely divided wood introduced through the inclined burners 32 and 34 located at the opposite sides 'of the furnace. However, it is contemplated to also use powdered coal or I may introduce powdered coal at one side and wood or sawdust at the other side of the furnace.

The furnace bottom or grate portion is formed a of a plurality of plates 36 arranged instepped returned flange 42 along one edge and an upturned flange 44 along the other edge. To each flange 44 is pivotally secured an adjustable damper 46 which is adapted to be manipulated so as to control the draft or amount of combustion air supplan at 36 in Fig. 6.

plied to the chamber 12. The dampers 46 may be adjusted individually or; if desired',.me'ans 4'7 may be provided for simultaneously moving them all in unison. 5

As shown inFig. 1,an air chamber 48 is provide d below the plates 36 and a pipe 50 connected to a suitable fan or blower-521s. adapted .to

supply air to said chamber under slight pressure. Or, if desired, chamber 48 may be evacuated so as to operate on a down draft principle.

The stepped plates 36 may extend straight across the furnace from side to side as indicated in Fig. 2 or the steps may be curved in plan as indicated at 36 in Fig. 3. In the arrangement of Figs. 1 to 3 inclusive, the different steps starting from front to back are all successively higher elevations. If desired, the lowermost step may be intermediate the front and back walls as indicated in Fig. 4. In this View the furnace is provided with sort of a Dutch oven portion 54.

In the form of furnace shown in Fig. 1, I prog; vide a by-pass connection 56 by means of which air can be passed directly from the chamber 48 to the combustion chamber 12, such passage of air being controlled by a damper 58. In the form of furnace shown in Fig. 4, the furnace is adapted to be fed to the dutch oven portion with finely divided fuel introduced through the inclined burner 32 This furnace is also provided with a by-pass connection 56 by means of which air can be passed directly from the chamber 48 to j the combustion chamber 12 such passage of air being controlled by a damper 58 Air is supplied to the chamber 48 by a suitable blower 52 and pipe 50 In the stepped arrangement of Fig. 4, the certain grate members 36 may be arranged in the form of concentric squares with the grates parallel with the walls 10 as indicated in Fig. 5 or they may be diagonally disposed as indicated in The damper for the curved grates of Fig. 3 may follow the same curvature as the grates and may be provided at their ends with suitable hinge lugs, the curvature being insufficient to interfere with the movement of the dampers. The dampers for the grates of Figs. 5 and 6 may be geared together or connected by any suitable linkage. Or, if desired, they may be simply separately and independently operable members. 105 Fig. 8 illustrates a modification in which there is a separate air chamber 60 provided below each plate 36. Each of these air chambers is supplied with air independently by means of a pipe 62,. these pipes being adapted to supply air to the respective chamber 60 either at the same or different pressures. By proper manipulation of the individual dampers 46 the contour of the fuel bed can be accurately controlled. That is to say, these various individual dampers can be adjusted to promote most efiiciently combustion at all parts of the fuel bed so that a substantially uniform amount of heat is generated at all parts of the bed. Heretofore, it has been difiicult to control combustion at difierent parts of the fuel bed and it is known to those skilled in the art that there is a decidedjtend'ency in grates heretofore constructed topermit a sort of channeling of the combustion air through certa'inlparts of the fuel bed. This results in faulty combustion taking place in certain parts of the furnace and more complete combustion taking place at other parts. My improved furnace provides for controlling the supply of combustion air to any desired .part .of the fuel bed so as to secure maximumaefficiency throughout the entire area thereof. e

While I have described quite specifically certain details of the embodiment ,of the invention illustrated, it is not tobe construed that I am limited thereto since various modifications and substitution of equivalents may be made by those skilled in the art without departing from the invention as defined in the appended claims.

What I claim is:-

1. A furnace of the class described including a stepped grate structure having a plurality of horizontal portions connected by vertical portions forming separate chambers between adjacent horizontal portions, individual air supply means communicating with each chamber and an individual damper controlling the flow of air from each chamber.

2. A furnace of the class described adapted. for burning'comminuted fuel in suspension and on a grate including a stepped grate, means for directing 'comminuted fuel downwardly toward the grate, a blower for delivering a current of air below the grate, means for by-passing part of the air from below the grate to a point above the grate between it and the fuel supply means, and means for controlling the discharge of some of the air supplied by the blower laterally through the stepped grate and effective to control the contour of the fuel bed and thus the distribution of fuel over such stepped grate.

JAY A; FREIDAY. 

